. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CIRCADIAN TIMING AT CELLULAR LEVEL 219 100 r 50 - I I. N N DAYS FIGURE 10. CAP frequency rhythms of Aplysia during the continuous presence, added at arrows, of anisomycin at 3 concentrations. The top is a control eye at 15°C in darkness, exhibiting periods of , , , 27, and 27 h. Periods at 10~8 M are , , , 32, and Periods at 10"7 M are 35 and 31 h. The inhibitor suppressed the rhythm completely at 10~6M, but the CAP activity continued. Successive noons (N) are the time axis. Triangles are c
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CIRCADIAN TIMING AT CELLULAR LEVEL 219 100 r 50 - I I. N N DAYS FIGURE 10. CAP frequency rhythms of Aplysia during the continuous presence, added at arrows, of anisomycin at 3 concentrations. The top is a control eye at 15°C in darkness, exhibiting periods of , , , 27, and 27 h. Periods at 10~8 M are , , , 32, and Periods at 10"7 M are 35 and 31 h. The inhibitor suppressed the rhythm completely at 10~6M, but the CAP activity continued. Successive noons (N) are the time axis. Triangles are calculated centroid points. From Jacklet, I980b. is expected for perturbations of a state variable (Tyson et al., 1976). The phase shifts plotted against circadian time in the cycle resulted in a PRC that indicates the agent's action on the basic timing mechanism. Figure 12 shows the PRC for anisomycin pulses. Greatest delays are at CT 0-3; advances are at CT 5-7. This apparent change in sensitivity to an inhibitor suggests that proteins necessary for clock timing are synthesized at specific times (Karakashian and Schweiger, 1976b). However, this proposition has not been tested, as it is not known which newly synthesized proteins are involved in the clock mechanism and which ones might be driven by the clock. Thus, a resolution must await the identification of specific clock proteins. In addition to Euglena and Aplysia eye, other preparations have supplied strong evidence to support involvement of protein synthesis in the oscillator. The rhythm in Acetabularia is phase shifted by three inhibitors: puromycin, cycloheximide, and anisomycin (Karakashian and Schweiger, 1976b). Using a liquid culture technique for Neurospora, Nakashima et al. (1980, 1981b) demonstrated phase-dependent phase shifting with cycloheximide. Even in Gonyaulax, where such experiments are difficult, there is positive evidence for phase shifting with cycloheximide (Walz. Please note that these images are ext
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
